The present invention generally relates to a lock plates inserting machine for key cylinder and a method for inserting lock plates into a key cylinder. More specifically, the present invention concerns the method and machine for automatically and mechanically inserting the lock plates into a plurality of respective lock plate receiving openings defined at regular intervals on the key cylinder in the axial direction thereof, in combination with such an operation that the required lock plates to be inserted are mechanically detected so as to correspond to respective serrations of a key.
In a well-known key cylinder, as shown in FIG. 1, a plurality of spaced serrations 2 having different widths are formed in parallel with each other on a key 1 in the longitudinal direction thereof and as many spaced lock plate receiving openings 4 as the key serrations 2 are defined on a key cylinder 3 in the axial direction thereof at the positions corresponding to the serrations 2 of the key 1 to be inserted. Since a plurality of lock plates 5 are inserted through springs 6 into the lock plate receiving openings 4 so as to correspond to the widths of respective key serrations 2, various kinds of key cylinders are produced by changing the arrangement of the key serrations 2.
Conventionally, although the springs 6 are automatically inserted into the lock plate receiving openings 4 of the key cylinder 3, the work for inserting the lock plates 5 corresponding to the key serrations 2 into respective lock plate receiving openings 4 of the key cylinder 3 is generally carried out through such a handwork that upon eye-measurement of the key serrations 2 by a worker, the lock plates 5 corresponding to respective key serrations 2 are inserted into the lock plate receiving openings 4 of the key cylinder 3 by being manually picked up. The foregoing work has been repeated six times by the worker owing to the fact that the key 1 generally has six rows of the serrations 2.
According to the above described handwork, however, not only the worker is required to be superior in skill and occasionally makes a mistake in measuring the key serrations 2 with his eyes, but also there exist considerable individual differences. Furthermore, on account of the handwork, it takes approximately thirteen seconds for the worker to insert all of the lock plates into one key cylinder, even in the fastest work by a skilled worker. Such being the circumstances, the aforementioned handwork is inferior in working efficiency, and as a result, the key cylinders have been undesirably produced at high cost.
Recently, there has been developed an electrically driven automatic inserting machine for automatically inserting the lock plates into the lock plate receiving openings of the key cylinder corresponding thereto in accordance with a result obtained by electrically detecting the key serrations one by one, through an optical sensor. However, the aforementioned electrically driven inserting machine includes such drawbacks that it is extremely complicated in construction and is formed into a large size and furthermore, it is unsuitable for incorporation into a production line, thus resulting in that the key cylinders have been produced at high cost. In addition, since the inserting machine of the above described type further includes such problems that it can not easily deal with the cases where a faulty detection of the key serrations, faulty insertion of the lock plates or the like has taken place and it can not be easily repaired in case of accident, it has a drawback that it has not been suitable for practical use.